Heat pumps · Error codes · Baxi
PFBaxi · HP60 / Baxi Assure HP55 High Temperature Monobloc ASHP (R290)
PF on a Baxi HP60 / Baxi Assure HP55 High Temperature Monobloc ASHP: Water flow sensor failure
Short answer
On a Baxi heat pump, PF means: Water flow sensor failure. The manual does not say whether the heat pump stops. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Water flow sensor failure.
Part involved: water flow / pressure.
Is it safe?
| Does the heat pump stop? | Not stated |
|---|---|
| Engineer needed? | Yes |
The manual does not say whether the heat pump stops.
Resetting itself: unknown.
Manual reset: unknown.
What you can check
- Note the exact code shown on the controller and when it appeared.
- Read the heating system pressure gauge and report the value to your installer (the manuals quote a minimum of about 1 bar cold).
- Check the filling loop is closed.
- In freezing weather do not leave the system switched off - the manuals warn water faults left unrepaired in winter can let the pump and pipes freeze.
- If the code persists or returns, contact a heat pump engineer.
What the engineer will check
- Diagnose per manufacturer service procedure (manual gives description only).
Who to ask for: heating / heat pump engineer (hydraulics).
Certification: None beyond heating competence (MCS installer recommended).
What you might notice
Sources
- Installation, user and service manual - Reversible monobloc air-to-water heat pump, outdoor unit HP60-4-1-PHMB to HP60-13-3-PHMB ↗ · 7888668 - v03 - 17072025 · page 58 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026